Electronic audio devices that are capable of producing and receiving electronic audio signals are arranged to couple the electronic audio signals to external audio devices such as recorders, players, amplifiers, microphones, and headsets. The audio input/output signals are often coupled to a headphone set (for example) using a standardized four-signal analog interface that uses, for example, contacts arranged co-axially in a tip-and-ring arrangement of a jack connector cabled to the headphone. The standardized four-signal analog interface for the electronic audio device includes a headset right sound output, a headset left sound output, a ground signal, and a microphone sound input. Each conductor in the headset jack is arranged to couple with an associated conductor (that corresponds in accordance with a location specified by the applicable standard) in a mating socket that is typically included in the electronic devices. Adapters are available so that jacks and sockets of differing sizes and arrangements can be successfully coupled together. Despite the conveniences provided by the standardized connectors, it is difficult to add functionality (such as noise cancellation as disclosed herein) to the electronic systems using the existing connectors for coupling external audio devices.